A theory is being explored that presupposes development of a network of nodes within the central nervous system to store and interrelate experiences codified as concepts. The theory holds that as individuals develop or species evolve, the complexity and number of concepts (size of nodal network) increases. (1) Wild and domesticated rats are provided the opportunity to enlarge the complexity and number of concepts by introducing conditions which foster cooperation, pair bonding, task oriented, sub-group formation, and communication network development. On the human level two avenues of development are proceeding. (2) A large-scale citation data base is being developed on the impact of the built environment on the health and welfare of people. This domain of research literature will be used as the main base for inquiry into a human CNS concept network, whose computer simulation and use may help human survival and further evolution. (3) A second compact data base has been developed. It consists of 169 1500-word statements written during 1976-77 for the project by leading investigators concerned with adaptation, environment and population. This project includes parts of discontinued 00823, 26, 28, 30, 31.